/*
 * Copyright (c) 2007 Aleksey Nikiforov
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of 'Aleksey Nikiforov' nor the names of other contributors 
 *   may be used to endorse or promote products derived from this software 
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.lex.input.effects.filter;



/**
 * Interpolates the given value over time.
 * 
 * @author lex
 *
 */
public class LinearFilter implements InputFilter {

	private float interpolationTime;
	
	private float remaining;
	private float time;
	private float travel;
	private float maxSpeed;

	/**
	 * To set no speed limit, use maxSpeed = 0.
	 * 
	 * @param interpolationTime
	 * @param maxSpeed
	 */
	public LinearFilter(float interpolationTime, float maxSpeed) {
		this.interpolationTime = interpolationTime;
		this.maxSpeed = maxSpeed;
	}

	public float getInterpolationTime() {
		return interpolationTime;
	}

	public void setInterpolationTime(float interpolationTime) {
		this.interpolationTime = interpolationTime;
	}
	
	public float getMaxSpeed() {
		return maxSpeed;
	}

	public void setMaxSpeed(float maxSpeed) {
		this.maxSpeed = maxSpeed;
	}

	public void feedInput(float input) {
		if (input != 0) time = interpolationTime;
		remaining += input;
	}
	
	public void update(float deltaT) {
		if (time > deltaT) {
			travel = remaining * deltaT / time;
			float travelLimit = maxSpeed*time;
			
			if (maxSpeed != 0 && travel > travelLimit) {
				travel = travelLimit;
			} else {
				time -= deltaT;
			}
			
			remaining -= travel;
			
		} else {
			travel = remaining;
			time = 0;
			remaining = 0;
		}
	}
	
	public float getOutput() {
		return travel;
	}

	public void clear() {
		time = 0;
		remaining = 0;
	}
	
}
